nuxt 2.16 has postcss8 by default

Version

@nuxtjs/tailwindcss: 6.3.1
nuxt: 2.16.0

Steps to reproduce

install nuxt 2.16 and add nuxtjs/tailwind, you get an error like:
FATAL Cannot destructure property 'nuxt' of 'this' as it is undefined. 13:32:58
which his actually covered here already: #572
but actually this is caused by installing postcss8, which is not needed anymore on nuxt 2.16 as it is now the default see https://github.com/nuxt/nuxt/releases/tag/v2.16.0

What is Expected?

do not install postcss8 for nuxt 2.16.. i tested it locally by just commeting out:

if (isNuxt2()) {
      // await installModule("@nuxt/postcss8");
    }

in dist/module.mjs
and eveything seems working perfectly fine :-)

What is actually happening?

it install postcss8 and breaks.